This is a phase IIIB, open-label controlled study to evaluate the use of Mycophenolate Mofetil (MMF, Cellcept) in post-liver transplant patients with renal impatient who are currently on Neoral (CyA). The objective is to evaluate whether MMF can be used as a mainstay immunosuppressive therapy in post-liver transplant patients with impaired renal fucntion, thereby decreasing the exposure to other immunosuppressive agents which are potentially nephrotixic. Safety and efficacy of each treatment regimen will be evaluated, including graft/patient survival, biopsy-confirmed or presumptive acute cellular rejection, and the indicence of adverse events, opportunistic infections and abnormal laboratory evaluations. The study will evaluate the use of MMF in combination with cyclosporine and corticosteroids in liver allograft recipients. Post-liver transplant recipients > 18 years of age who meet all study entry requirements will be randomized (computer generated) with equal allocation to two groups. Both groups will have Imuran discontinued. Group A will be maintained on MMF 1. 5 gm bid, prednisone, and Cya will be tapered to 50% at week 2 and discontinued at week 4. Group B will be maintained on MMF 1.5 gm bid, prednisone, and CyA will be tapered to 50% at week 2 and maintained throughout the study. Patients will be followed for 1 year post-enrollment. Glomerular filtration rate (GFR) using iohexol clearance will be measured on both groups of patients at enrollment, and at 1, 2, 4, 7, and 12 months following enrollment. The primary efficacy parameter will be measured by the change in GFR from baseline to week 28 post-randomization. A total of 30 patients will be enrolled at 3 centers. It is expected that 10 patients will be enrolled at Duke.